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Muddy Susquehanna in Harrisburg, Pennsylvania
This page contains archived content and is no longer being updated. At the time of publication, it represented the best available science. However, more recent observations and studies may have rendered some content obsolete.
Traveling northward from the Gulf of Mexico, Tropical Storm Lee carried heavy rain to the northeastern U.S. in early September 2011. The rain swelled multiple rivers, including the Susquehanna.
Authorities evacuated residents of Harrisburg, Pennsylvania, then nervously watched the city’s 41-foot (12-meter) high levees, The Philadelpha Inquirer reported. By September 11, the river had receded. The Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite captured this natural-color image on September 10.
Loaded with sediment, the Susquehanna flows through the city, but appears confined within its embankments. According to the Advanced Hydrological Prediction Service of the U.S. National Weather Service, the Susquehanna River fell rapidly between September 9 and 12, 2011, from major flood stage to below flood level.
The levees withstood the river’s pressure in Harrisburg, but other communities along the banks of the Susquehanna were less fortunate. The river stressed levees “beyond what they were built to withstand,” said The Philadelpha Inquirer. The paper reported that some towns suffered more from Tropical Storm Lee than they had from Hurricane Agnes in 1972.
By September 9, 2011, President Obama declared an emergency in New York and Pennsylvania, Agence France-Presse reported. Roughly 100,000 people had been forced to evacuate, and the death toll stood at five. By September 11, the death toll for Pennsylvania had climbed to seven.
NASA Earth Observatory image created by Jesse Allen and Robert Simmon, using EO-1 ALI data provided courtesy of the NASA EO-1 team. Caption by Michon Scott.
Acquired September 10, 2011, this natural-color image shows the muddy Susquehanna River flowing through Harrisburg, Pennsylvania.